"Best Northern Lights I've Seen in Years"

October 13, 2012, 10:36:59 AM EDT

"Best Northern Lights I've Seen in Years"

People in the United States and Canada had a second night's peek at the aurora, which is rare at that latitude.

Storified by Accu Weather · Tue, Oct 09 2012 06:32:19

People in the United States and Canada had a second night's peek at the aurora, which is rare at that latitude. An AccuWeather meteorologist said that Monday night's show was the "the best Northern Lights I've seen in years." However, "I think that our window for viewing the Northern Lights from this CME (coronal mass ejection) is over," AccuWeather.com Astronomy blogger Mark Paquette said.

Ghost Flamemusubk

Good space conditions for an aurora are hard to forecast. Other than analyzing satellite information, looking at the strength of the solar wind and proton density can help indicate the strength a geomagnetic storm. The stronger the geomagnetic storm, the more likely viewers would be able to see the Northern Lights farther south than usual.

"To make it as simple as possible," AccuWeather.com Astronomy blogger Mark Paquette said, "the most reliable measure of whether or not we will see the Northern Lights Tuesday night is the inter-planetary magnetic field (IMF for short)." When the IMF points south (southward Bz), it partially cancels out the Earth's magnetic field and allows energy from the solar wind to penetrate the Earth's atmosphere. Right now, the Bz is positive. There are no signs of Bz becoming negative Tuesday or Tuesday night so I think that our window for viewing the Northern Lights from this CME is over."

The most difficult part of forecasting whether a CME (coronal mass ejection) will have an impact on the Earth is the arrival time. A coronal mass ejection is basically a storm, a burst of energy that is released from the Sun's surface. However, AccuWeather.com Astronomy blogger Mark Paquette said that a rule of thumb is that the massive release of solar wind and magnetic field from the surface of the Sun usually takes 36-48 hours to reach the Earth.

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Aurora 8.10.012Nightskyhunter On Flickr

Aurora 8.10.012Nightskyhunter On Flickr

Aurora IIIFriesen Creative

Northern lights from the UP @twitterlessDylan http://pic.twitter.com/Nwc44XYhJoey Felker

#tmt The aurora borealis (Northern Lights) as seen from County #Louth last night by Shane Murphy http://yfrog.com/gzwwbscxjThe Meteo Times

If you're looking for more aurora pictures, here are some of the best from Sunday night: